DUAL BATTERY CHARGER HAVING DUAL OUTPUT

• US 3,624,480 A
• Filed: 11/12/1970
• Issued: 11/30/1971
• Est. Priority Date: 11/12/1970
• Status: Expired due to Term

• Current Assignee: Donald L. Cummins, Robert W. Campbell
• Original Assignee: Donald L. Cummins, Robert W. Campbell
• Inventors: Cummins, Donald L., Campbell, Robert W.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/088,590
• Time in Patent Office: 383 Days
• Field of Search: 320/7,12,15-19,22,39,40,64,68,61 322/28,36
• US Class Current: 320/123
• CPC Class Codes: H02J 7/1423 with multiple batteries

Abstract

First and second batteries are connected in series between a point of constant reference potential and the output terminal of a first full-wave bridge rectifier. The output terminal of a second full-wave bridge rectifier comprising silicon-controlled rectifiers (SCR) is connected to a junction between the batteries. The respective legs of the first and second rectifiers are each connected to the same output winding of the stator of an alternator. A first voltage detector responsive to the voltage across the first and second terminals causes the SCR'"'"''"'"'s to be nonconductive when the voltage across the first and second terminals is less than a first predetermined voltage. A second voltage detector controls the current through the field winding of the alternator in response to the voltage at the junction between the batteries to maintain a second predetermined voltage thereat. The drop in current and therefore voltage at the junction occurring an instant after the SCR'"'"''"'"'s are rendered nonconductive causes the second voltage detector to increase the current and voltage at the first output to increase by an amount sufficient to reestablish the second predetermined voltage at the junction.

Claims

2. In an electrical system for a vehicle:

a. first and second full-wave bridge rectifiers having respectively first and second output terminals and a plurality of AC input terminals, said second bridge rectifier comprising at least one controllable unidirectional current conducting device;

b. first and second batteries connected in series between a point of constant reference potential and said first output terminal, said batteries defining a junction therebetween connected to said second output terminal;

c. a stator having a plurality of output windings, each said winding connected to a corresponding AC terminal of said first and second rectifiers;

d. a field winding connected with at least one of said output windings and energized thereby, and e. first and second voltage detection means, said first detection means responsive to the voltage across said first and second output terminals and operative to render said controllable device nonconductive when the voltage across said first and second terminals is less than a first predetermined voltage, and said second voltage detection means responsive to the voltage at said junction and operative through a field current control means to control the current in said field winding to maintain a second predetermined voltage at said junction, whereby the voltage at said junction is continuously maintained at said second predetermined voltage and the voltage at said first output terminal is maintained substantially at the sum of first and second predetermined voltages when said controllable device is nonconductive.

3. A vehicle charging system comprising:

a. alternator means controllable to produce one of first and second output voltages;

b. first and second batteries connected in series and defining a junction therebetween, one side of said series connected batteries being connected to a point of constant reference potential;

c. means responsive to the voltage between the other side of said series connected batteries and said junction and operative to connect said one output voltage of said alternator to said other side of said series connected batteries when said voltage between said other side and said junction is less than a first predetermined voltage whereby both said batteries are charged and to connect the other of said first and second output voltages to said junction when the voltage between said other side and said junction is greater than said first predetermined voltage, whereby one of said first and second batteries is charged; and

d. a voltage regulator respoNsive to the voltage at said junction and operatively connected with said alternator means to maintain a second predetermined voltage at said junction, whereby said regulator means controls said alternator means to produce said one of said first and second output voltages when said one output voltage is applied to said other said side of said series connected batteries and to control said alternator means to produce said other of said first and second voltages when said other voltage is applied to said junction.

4. A motor vehicle battery charging system for charging at least two batteries comprising:

a. an alternating current generator having an output winding and a field winding;

b. first rectifier means having AC input terminals connected to said output winding and first and second direct current output terminals;

c. first and second batteries;

d. means connecting said batteries in series across said direct current output terminals of said first rectifier means with said first battery connected between said first output terminal and a junction and said second battery connected between said junction and said second output terminal;

e. a voltage regulating means including field current control means connected with said field winding and said output winding of said generator, said voltage regulating means including voltage sensing means connected between said junction and said second direct current output terminal of said rectifier means whereby the output voltage of said generator is regulated to a value which is a function of the voltage appearing between said junction and said second direct current output terminal of said first rectifier means;

f. second rectifier means having direct current output terminals and AC input terminals connected with said output winding; and

g. means responsive to the voltage appearing between said first direct current output terminal of said first rectifier means and said junction causing a direct voltage from said second rectifier means to be applied to said junction when the voltage between said first output terminal and said junction reaches a predetermined value to thereby substantially terminate charging of said first battery and charge said second battery from said second rectifier means.